@uhoh I don't have a definitive answer but would say that fiber took over gradually, with the biggest growth in the 1995 - 2005 period.
I remember in the 1990s it was hit or miss whether you would get a fiber or satellite connection, with a satellite connection being very noticeably more laggy than a fiber connection.
There are maps like this available to tell you the in-service date of all the cables still operating.
And historical cables like TAT-1 (the first transatlantic telephone cable) and TAT-8 (the first fiber-optic transatlantic cable) get their own Wikipedia pages.
@ThePhoton I remember the excitement about fiber, and a few ups and downs in the optical communications industry before it became more mature. It seems you have some interesting information and perspective to offer, please feel free to post an answer; it's a pretty flexible site and answers are generally well-received as long as they partially address aspects of the question.
If you are able to find any maps at all that have connections to satellite ground stations for uplink/downlink, that would be of particular interest to readers there!
